Deflection control electron discharge device



Oct. 21, 1952 ADLER DEFLECTION CONTROL ELECTRON DISCHARGE DEVICE Filed Jan. 19, 1.950

ROBERT A DLER INVENTOR.

HIS ATTORNEY Patented Oct. 21, 1952 UNITED STATES DEFLECTION CONTROL ELECTRON DISCHARGE DEVICE Robert Adler, Chicago, 111., assignor to Zenith Radio Corporation, a corporation of Illinois Application January 19, 1950, Serial No. 139,403

6 Claims.

This invention relates to electron-discharge devices and more particularly to such devices of the deflection-control type.

Deflection-control amplifiers as such are well known in the art, and it is conventional to provideamplification of an input signal by deflecting a formed electron beam between a pair of anodes in accordance with that signal. It is not generally possible to obtain with-a deflection-control system amplification comparable to that obtainable with a control system comprising a cnven tional intensity-control grid, and for this reason, deflection-control is commonly utilized only in certain specialized applications. However, defiection-control affords certain well known advantages over intensity-control, as for example, in push-pull or balanced circuit arrangements.

In order to obtain the advantages of deflectioncontrol while increasing the obtainable amplification, it is known to arrange a. plurality of deflection-control systems in cascade along .the path of a single formed electron beam and to connectthe output electrodes of each system to the input electrodes of the succeeding system. This scheme may not be carried out indefinitely, however, due to the difficulty of collimating an electron beam over a long path.

It is, therefore, a primary object of the present invention to provide an improved multi-stage defiection-control electron-discharge device.

It is a further object of the invention to provide an improved deflection-control electron-discharge device which afiords the advantages of prior-art arrangements while avoiding one or more of their disadvantages.

An electron-discharge device constructed in accordance with the present invention comprises an electron gun including a cathode and an accelerating electrode for projecting a plurality of formed electron beams. A first control system, comprising electrodes positioned along the path of one of the beams, includes an intensity-control grid followed by an anode, and a second control system, comprising electrodes positioned along the path of another of the beams, includes a deflection-control electrode which is electrically connected to the anode of the first system. Preferably, the anode of the first system is integrally constructed with the deflection-control electrode of the second system.

. The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with further objects and advantages thereof, may best be understood, however, by

reference to the following description taken in connection with the accompanying drawing, in the several figures of which like reference numerals indicate like elements, and in which:

' Figure 1 is a perspective view of the internal construction of an electron-discharge device, together with a schematicrepresentation of its circuit connections;

Figure 2 is a similar view of another embodiment of the invention, and

Figures 3 and 4 are cross-sectional views of further embodiments of the invention together with schematic representations of their circuit connections.

In Figure 1, an electron-discharge device comprises an electron gun including an elongated cathode l0 havingan emissive surface I I, an auxiliary electrode l2 electrically connected to cathode IB and having portions substantially coplanar with emissive surface I I, a focussing electrode l3 having a slot opposite emissive surface I I, and an accelerating electrode I4 having a slot 15 bounded by a pair of opposed lips 16 extending into the slot of focussing electrode l3, substantially as dise closed and claimed in the copending application of Robert Adler, Serial Number 68,285, filed December 30, 1948, now U. S. Patent No. 2,559,037, issued July 3, 1951, for Electron-Discharge Devices of the Focussed-Beam Type, and assigned to the present assignee.

A first control system, comprising electrostaticdefiection electrodes ll and I8 and a pair of anodes l8 and 2B, is positioned along the path of the lower transverse portion of theelectron beam emerging from slot 15 of accelerating electrode It, anodes l9 and 20 having active portions on opposite sides of that path. A second similar control system, comprising electrostatic-deflection electrodes 2! and 22 and a pair of anodes 23 and 24, is positioned along the path of the upper transverse portion of the beam projected through slot- 15 of accelerating electrode 14. A suppressor electrode 25, which may conveniently be grounded, is disposed between the anodes of each system in order to suppress secondary'electron emission in a manner well known to the art.

Anodes l9 and 20 of the first electrode system are electrically connected respectively to electrostatic-deflectionelectrodes 2| and 22 of the sec- ,7 these pairs of electrodes from a single sheetmetal stamping.

The entire electrode structure is supported within an evacuated envelope, indicated schematically at 26, which may be evacuated, gettered, and based in any convenient known manner.

Cathode H), auxiliary electrode l2, focussing electrode l3 and suppressor electrode are connected to ground. Accelerating electrode M is connected to a suitable source of positive unidirectional operating potential, conventionally designated B+, through a resistor 21. An input signal is applied from any suitable source (not shown) between a pair of input terminals 28 and 29 at opposite terminals of the primary winding 3!) of an input transformer 3|, and the secondary winding 32 of input transformer 3| is connected between electrostatic-deflection electrodes l1 and I8. Anodes |9 and 20 are connected to 13+ through resistors 33 and 34 respectively, and anodes 23 and 24 are connected to opposite terminals of the primary winding 35 of an output transformer 36, a center tap 31 of primary winding 35 being connected to 13+. A pair. of output terminals 38 and 39 are provided across the secondary winding 49 of output transformer 36. In operation, cathode |0, auxiliary electrode l2, focussing electrode I3 and accelerating electrode |4 cooperate to project a formed sheetlike electron beam of substantially rectangular cross-section in the manner described in detail in the above-identified Adler application. The lower portion of the beam is projected between electrostatic-deflection electrodes [1 and I8 and is transversely deflected in accordance with the input signal applied between terminals 28 and 29,. An amplified signal is thereby produced between anodes IS and 29 in a manner well known in the art.

v Anodes l9. and 2|) are electrically connected respectively to the electrostatic-deflection electrodes 2| and 22 associated with the upper portion of the beam. This portion of the beam is thereby deflected in accordance with the amplified signal appearing between anodes l9 and 20, and a further amplification is effected at anodes 23 and 24. The output signal appearing between outputterminals 38 and 39 may be applied to further amplifying and/or utilizing means (not shown).

Thus, in effect, a pair of electron beams are projected from cathode l8 and are separately controlled by electrostatic-deflection electrodes I8 and 2|, 22 respectively. A first amplification of the input signal is effected in the lower electrode system, and the amplified signal is utilized as the input to the second or upper electrode system. Consequently, two stages of amplification are effected within a single device. The arrangement has the advantage, however, over known arrangements in which the deflectioncontrol systems are arranged in cascade along the path of a single electron beam, that the am plified signal obtained at the output of the first system is utilized to control a separate and distinct portion of the electron emission with a result that detrimental defocussing effects are avoided.

In Figure 2, representing an embodiment of the invention, intensity-control is utilized in the first system and deflection-control in the second. The first control system comprises a second focussing electrode 50, an intensity-control grid 5|, a third focussing electrode 52, a screen grid 53, and an anode 54. Preferably, in order to obtain maximum transconduotance of control grid 5|, the distance between slot |5 of accelerating electrode l4 and control grid 5| is made greater than the width of slot I5, as disclosed and claimed in the copending application of Robert Adler, Serial No. 7,864 filed February 12, 1948, for Electron-Discharge Devices, now U. S. Patent 2,511,143 dated June 13, 1950, and assigned to the present assignee. Third focussing electrode 52 and screen grid 53 constitute a convergent electron lens for refocussing electrons passed by control grid 5| in the manner described in the first-mentioned copending Adler application.

The second electrode system, positioned along the path of the upper transverse portion of the beam projected through slot |5, comprises a pair of electrostatic-deflection electrodes 55 and 56 and a pair of anodes 5'! and 58 which have active portions on opposite sides of, and are preferably positioned symmetrically With respect to, the path of the beam. In accordance with the invention, anode 54 is electrically connected to electrostatic-deflection electrode 55, and electrode 56 is electrically connected to accelerating electrode '|4. Preferably, anode 54 and deflection electrode 55 are integrally formed from a single piece of sheet-metal to'provide the desired electrical connection. The electrode structure is supported within an evacuated envelope schematically represented at 59.

Cathode l9, auxiliary electrode l2, and focussing electrodes I3, 50, and 52 are: all connected to ground, and accelerating electrode I4 is connected to 3+ through resistor 21 and to ground through a condenser 60. A pair of input terminals 6| and 62, respectively connected to ground and coupled to control grid 5| by means of a condenser 63, are provided, and control grid 5| is returned to ground through a resistor. 64. Screen grid 53 is directly connected to 13+ or alternatively to accelerating electrode l4, and anode 54 is connected to 3+ through a resistor 65. Anodes 5'! and 58 are connected to opposite terminals of the primary winding 66 of an output transformer 61, a center tap 68 on primary winding 66 being connected to B+. Output terminals 69 and 78 are provided across the secondary winding H of output transformer 61.

In operation, an input signal applied between terminals 62 and 6| from any suitable source (not shown) effects intensity-control of the lower transverse portion of the electron beam projected through slot |5 in the manner described in the above-identified Adler applications. An amplified signal is therefore produced at anode 54. This amplified signal is applied directly toelectrostatic-defiection electrode by virtue of the internal electrical connection between these electrodes, and resistors 21 and are made equal to maintain the average potentials of -electrostatic-deflection electrodes 55 and 56 at'a common value. Consequently, the amplified signal produced at anode 54 effects a corresponding transverse deflection in the upper portion of the beam, and. an amplified output signal appears between terminals 69 and 10.

In the embodiment of Figure 3, the electron gun comprises a straight filamentary cathode 88 flanked by a pair of substantially cylindrical beam-forming electrodes 8| and 82. An accelerating electrode 83 having apertures 84 and 85 is provided to produce a positive potential gradient adjacent cathode (near but not directly at the surface of the cathode) in a direction substan- 5 tially perpendicular to "a plane including the axes or b'eamefo'rm-ing. electrodes 8'I. andBZQ-Preferablyybam-forming electrodes 8| iand'02 are in.. dividually. constructed of a diameterroizsubs'tanez tiiilly '60 sof': their center-to-center "spacing and are operatedat a potential near that of cathode 80; "forc'onveniencei cathode 80 and beam-fume ing electrodes BI and 82 may all be operated at substantially ground ;.potential. .The electron gun," comprising cathode B0, beam-forming .elec' trodes 8 I i and 82;: and -accelerating. electrode -83, functions; toiproject arpair of oppositely directed electron.beamsythrough; apertures 84 and 185 respectively. :3 :first 1 control. isystem; positioned along the path of the beam. projected through aperture 84, comprises; :a pair of electrostaticidefiection, electrodes 86 and 81,:the latter being directly connected to accelerating electrode 83, Ajopair of anodes-:88 -p,nd.;891are provided with active por-' tions ongopposite sides eoitheopath: of the beam in, a-mann'er; well known inthe art.-

- 15. second; control system, comprising electro; staticg-defiectionzelectrodes 90 and 8| and anodes 32 an d .93, is positioned along the-path; of the beam projectedthrpugh aperture 8 5. In accordance with heinven io anodes. 88 d 8 ar electrically connected respectillely. to electroe atiq-deiiecti n. e des- 190 a 9.1. The .en-

tireelectrodestructure; is=;.,supportedg-within an o evacuated ;e n;velope schematically. represented .C ihQ 80 and beam-tow e e t od s and 82 mayi cgnvenientlybe maintained at sub-. stantiallyfground potential, {and accelerating ele rode 8 3 U;is1connectegl; to 13+ through a resistor flfi andto ground through a bypass. condenser 96., An input signal source 9'! is connected between electrostatic -deflection electrode 86 and;,ground,; and anodes 88 and 89 are connected to B+ through resistors 08 and 99 respectively. Anodes 92-and03'are" coupled to 13+ by means of resistors I and, IOI respectively,-

and a pair of output terminals ,.I02' enofms are coupled to anodes 92 and 93" respectiv'ely by means of condensers I and I05.

In operation, the electron beam projected through aperture 84 is defiected in accordance with theinput signal from source 97, and-the amplified signal appearingtlqetween anodes B8 and 891; is applied between deflection electrodes 90i;and. slgassociated with, the beam projected through aperture 85. An amplified output signal istherefore developed between anodes 92'apd93.

In the embodiment of Figure 4, the electron gun comprises a centrally located cathode H0, preferably cylindrical, and an accelerating electrode'positioned substantially concentrically with respect to cathode H0. Accelerating electrode III is provided with four equally spaced similar slots H2, H3, H4, and H5, and focussing electrodes H6 are provided between slots II2- II5 and cathode I I0. Cathode H0 is provided with a heater element (not shown) and is preferably operated at a common potential with focussing electrodes H6. Accelerating electrode III may conveniently be formed as a solid cylinder from which material has been removed to provide the desired number of slots or apertures.

A air of electrostatic-deflection electrodes I I1 and H8 are disposed on opposite sides of the path of the beam projected through slot H2; similarly, electrostatic-deflection electrodes H9, I20; I2I, I22; and I23, I24 are positioned on opposite sides of the paths of the respective beams projected throughslots .I I3, m, and Us.

A final anode I25, which may conveniently be of cylindrical configuration, is substantially concentr'ically disposed with respect to cathode I I0, and:

deflection thereof in.-one transverse direction. Deflection electrodes H8, I20, I22, and:l24,'co'nstituting one of each pair, are electrically'.connected to acceleratingelectrode I II forz-operation at a common potential therewith. I

. Deflection electrode III, associated withr-the beam projected through. slot H2, serves as; aninput electrode, while intercepting anode I29,

associated with the beam projected through slot- II5, constitutes a convenient output electrode. Each of the other intercepting anodes, in accord-- ance with the present invention, is electrically connected to the remaining electrostatic defiec tion electrode of the next system in otheri words, intercepting anode I26 is-electrically connected to deflection electrode H9, intercepting "anode.

I2? to deflection electrode I2I, nd intercepting anode I28 to deflection electrode I23. Preferably, each of these electrical connections fis, efiected by constructing the parts to be connected or aunitary piece of sheetmetal. I j

The entire electrode structure is supported within an evacuated envelope I30 in any con-.-,-

venient manner. i j Cathode IIO -and focussing electrodes H6 are. preferably operated at ground potential, and final anode I25 is connected to.B.-I-.- vAccelerating electrode I I I is connected to a source B1+ of a lower. positive unidirectional operating. potential than that of source B-I Aninput signal source is connected between electrostatic-deflectionelectrode H1 and B1I, and interceptin finodes I26, I21, I,28 a nd I'29 are connected to fi l through resistors I32, I33, I34, and ,I respec tively. Output terminals I36 and l3'l-are-con-jv nected respectively to intercepting anode .I 29 and to ground.

In operation, resistors 32, I33, ,and I34 are equal in magnitudeand of such size as-tomaintain deflection electrodes H9; I2I and-I23 at an average potential-equal to that of source Br-I Th inP-ui e i f qm o e I3 ap li d .t. .l. flection electrode II], transversely. deflects .the electron beam projected through ,slot H2 ,so that. anamplii led signal appears at intercepting anode, I26. This amplified signal isutilized; as the input. signal to the nextsystem, and further amplification is progressively accomplished by means of the successive control of the electron beams projected through slots H3, H4, and H5. Thus, four stages of deflection-control amplification are accomplished within a single envelope, the final output signal appearing between terminals I36 and I41. Of course, a larger or smaller number of stages may be included within the structure as desired, and the arrangement may be adapted for push-pull operation at the expense of greater complexity of construction.

Thus, the invention provides a new and improved type of deflection-control electron-discharge device comprising at least two control systems, at least one of which is of the deflectioncontrol type, which are arranged in cascade with respect to the signal to be amplified but in parallel with respect to a common electron source. Thus, each pair of deflection-control electrodes operates on a well-formed electron beam, and

thedetrimentalidefocussing eifects of prior-art arrangements are avoided;

- While particular embodiments of the present and modificationsas fall within the true spirit and scope of the invention.

v1.. An' electron-discharge device comprising: an electron gun including-a cathode and an accelcrating electrodeior projecting a plurality of formed electron beams; a" first control system comprising electrodes positioned along the path of one of said beams and including an intensitycontrol grid followed 'by an-anode; and a second control 'system'comprising electrodes positioned along the path of another of said beams and including a deflection-control electrode electrical ly connected to said anode.

2. An electron-discharge device comprising: an electron gun including a cathode and an accelcrating electrode for projecting a plurality of formed electron beams; a first control system comprising electrodes positioned along the path of one of said beamsand including an intensitycontrol grid followed by an'anocle; a second control system comprising a pair of electrostaticdeflection electrodes positioned on opposite sides of-the path of another of said beams; and means electrically connecting one of saidelectrostaticdeflection electrodes with said anode.

3'. An electron-discharge device comprising: an electron gun including a cathode and an accelcrating electrode for projecting a plurality of f ormed electron beams; a first control system comprising electrodes positioned along the path of one of said beams and including an anode; a second control system comprising a pairof electrostatic-deflection electrodespositioned on opposite-sides of the path of another of said beams; and means electrically connecting one of said electrostatic-deflection ele'ctrode's'with said anode and the other of said electrostatic-deflection electrodes with said accelerating electrode.

4. electron-discharge device comprising: an electron gun including a cathode and an acceleratingelectrode for projecting a plurality of formed electron beams; a first deflection-control system positioned along the path of one of said beams and including an anode and a pair of electrostatic-deflection electrodes; means for operating said accelerating electrode and one of said electrostatic-deflectionv electrodes-s at'a conr-' monpotential; and a second.v deflecticnvcontrol system positioned along the path-of'another of. said beams and including-a pair of electrostatic? deflection electrodes. one of which is electrically connected to said anode and the other of which is electrically connected to said accelerating electrode.

5. An electron-discharge device comprising: .an electron gun including a centrally located cathode and an accelerating electrode positioned substan-v tiallyconcentrically..with respect to said cathode and having 11. slotsior projecting n formed-elem tron beams, n being an integer greater than unity; 11 pairs of electrostatic-deflection electrodes individually positioned on opposite sides of the paths of said respective beams; n'intercepting anodes disposed between said final anode and said respective pairs of electrostatic-defied tion electrodes forindividually intercepting saidrespective beams upon deflection thereof in one transverse direction: means for operatingone' of each of said pairs of electrostatic-deflection else-- trodes at a common potential with said accelerat ing electrodes; and means electrically connecting one of said intercepting anodes with theother of the pair of electrostatic-deflection electrodesassociated with adifierent beam.' 6. In anelectron-discharge device, an electron gun comprising: arectilinearfilamentary cathode; a pair of substantially cylindrical beamforming electrodes flanking said cathode and in dividually having 'a diameter of substantially 60 per cent of the center-to-center spacing-between said electrodes; and a slotted accelerating electrode for producing a positive potential gradient adjacent said cathode in a direction substantiallyperpendicular to a plane including the axes'of said beam-forming electrodes; ROBERT ADLER.

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